Inspection of four-sensor falls detector

The studies presented in this article are the continuation of previous work to develop a mobile fall detector. The algorithm is based on a discrete wavelet transform of the signals from the sensors available at the detector and a linear support vector machine as a classifier. Fisher score method is used for feature selection in the proposed algorithm. As a result of reducing the number of features, the number of support vectors has been also reduced — it has a direct impact on the upper estimate of the classification error. On the basis of the obtained results, the classifier parameters have been calculated. This allows presenting the developed concept in the field of ROCROCROC curves (Receiver Operating Characteristics) and their comparison with the results obtained for individual sensors. The developed concept gives much better results than each of the sensors acting independently. The findings of this study have given very good results in comparison with the previous findings, with a significant reduction in the number of required features. Due to the close relationship between the number of training data and the number of support vectors which directly affect the upper estimate of the classification error, the number of features has been reduced. Finally, satisfactory results have been obtained with the reduction of the number of features from 38 to just six, ensuring that the upper estimation of the classification error in the set of the new test data does not exceed 5.3%.[b]Keywords[/b]: falls detection, data fusion, discrete wavelet transform, support vector machin